Chapter 24

Question 1

how will a compass align itself in relation to the magnetic field

Answer 1

it will rotate to line up with the magnetic field

Question 2

what produces a magnetic field

Answer 2

magnets, current carrying wires, loops, and coils

Question 3

how do magnetic fields interact with moving charges particles and electric currents?

Answer 3

they exert forces on them

Question 4

how do like poles interact? what about opposite

Answer 4

like poles repel while opposite poles attract

Question 5

what happens if you cut a magnet in half

Answer 5

you have two smaller magnetics,each with their own poles

Question 6

What are magnetic materials? How do they interact with the poles of a magnet

Answer 6

they are materials that are attracted to a magnet, they are attracted to both ends

Question 7

how do you tell the direction of a magnetic field on a compass

Answer 7

the magnetic field is in the direction that the north pole of a compass needle points

Question 8

the magnetic field of a magnet points ______ from the north pole and _______ the south pole

Answer 8

away; toward

Question 9

where do magnetic field lines start? where do they end? do they actually end

Answer 9

they start from north and go to south but they travel through the magnet so they don’t actually end but form a closed loop

Question 10

when a compass is placed near a current carrying wire, the compass moves. Why?

Answer 10

current carrying wires produce a magnetic field that goes in the direction of the finger curl with the right hand rule

Question 11

what shape are the magnetic field lines around a wire?

Answer 11

they form a circular shape that decrease with distance

Question 12

for a looped wire, what type of field lines are seen

Answer 12

it looks like a dipole with circles following through the center of the loop, around the outside and back through the center

Question 13

for a current in a straight wire going up, what is the direction of the magnetic field?

Answer 13

counterclockwise

Question 14

for a current in a straight wire pointing down, what is the direction of the magnetic field

Answer 14

clockwise

Question 15

what type of magnetic field does a solenoid form

Answer 15

a strong, internal uniform field and a weak external field

Question 16

what does the strength of the magnetic field in a solenoid depend on

Answer 16

it depends on the length of the wire and the number of coils it has

Question 17

For a particle in a magnetic field, at what velocity does the particle not experience a force

Answer 17

when it is not moving

Question 18

For a particle in a magnetic field, at what angle does the particle not experience a force

Answer 18

when it is moving parallel to the magnetic field

Question 19

When does a particular experience a force from the magnetic field

Answer 19

when it moves perpendicularly from the magnetic field, the force exerted on the particle is always perpendicular to the plane containing v and B

Question 20

what angle provides the greatest force on a moving particle

Answer 20

when it moves 90° from the magnetic field

Question 21

if you have a negatively charged particle, how does the direction of the force from the magnetic field relate to the right hand rule

Answer 21

it is opposite from what we expect

Question 22

for a particular moving perpendicular to the uniform magnetic field , what motion does it undergo?

Answer 22

uniform circular motion at a constant speed

Question 23

what direction does a negative charge orbit when in a uniform magnetic field

Answer 23

it orbits int he opposite direction of the positive charge

Question 24

if a current carrying wire is parallel to the magnetic field, what is the force exerted on it

Answer 24

it is zero

Question 25

what happens when two current carrying wires are in a magnetic field

Answer 25

they exert forces on eaachother

Question 26

if two current carrying wires are in a magnetic field and they have a current in the same direction what is the force between them

Answer 26

it is attractive

Question 27

if two current carrying wires are in a magnetic field and they have a current in opposite directions what is the force between them

Answer 27

it is repulsive

Question 28

if two current carrying loops have opposite currents, what is the force between them

Answer 28

it is repulsive

Question 29

if two current carrying loops have the same currents, what is the force between them

Answer 29

it is attractive

Question 30

what characteristics does a current loop share with a bar magnet

Answer 30

it has a dipole and a north and south character

Question 31

if a loop has a magnetic dipole, what does it experience in a magnetic field

Answer 31

no net force but it experiences a net torque

Question 32

what is the magnetic dipole moment

Answer 32

it is the area x the current of a loop. It affects the torque

Question 33

what angle does the torque depend on in a loop

Answer 33

it depends on the angle between the magnetic dipole and the magnetic field

it is maximum at 90° (perpendicular) and is zero when parallel with the magnetic field

Question 34

how will a magnetic dipole act in a uniform magnetic field

Answer 34

it will rotate to line up with it

Question 35

what is a ferromagnetic material

Answer 35

it is a material that is strongly attracted to magnets that can be magnetized

Question 36

why does magnetism occur

Answer 36

electrons have an inherent magnetic moment

Question 37

what electrons give an atom a net magentic moment

Answer 37

unpaired electrons

Question 38

what type of atoms do ferromagnetic materials have

Answer 38

they have atoms that have net magnetic moments that tend to line up and reinforce eachother to create a magnetic moment

Question 39

how is a material magnetized

Answer 39

when an external magnetic field is applied, the domains in the material will align and grow at expense of other domains which creates a net magnetic moment that is attracted to the magnet

Question 40

what are magnetic domains

Answer 40

they are regions of aligned magnetic moments in a ferromagnetic material